1. Field of the Invention
The present invention concerns a novel method and structure for batch processing of GaAs-AlGaAs light-emitting diodes.
2. Description of the Prior Art
Light-emitting diodes having a GaAs-AlGaAs double heterostructure, such as described in an article by C. A. Burrus in Proceedings of the IEEE, Feb. 1972, pages 231-232, are known to make efficient light sources for optical communications systems. In the conventional fabrication of these devices, the diodes are partially processed on a common wafer, which is cut into individual dice for mounting and further fabrication. The step of etching the light-emitting "well" in the substrate is generally performed on an individual basis which must be carefully controlled and visually observed. Attempts to electrolytically etch several diodes at once on a common wafer have not been successful since short-circuits frequently occur across one diode which destroys the usefulness of the entire wafer. A recent process has been found which now permits a controlled preferential etching of a layer of GaAs material on a layer of AlGaAs which resists the etching. This is described in a co-pending U.S. application, Ser. No. 381,962 filed July 23, 1973 and assigned to the same assignee as the instant application.